1. Field of the Invention
The invention relates to the isolation, selection, and application of novel strains of bacteria which have the ability to control the weed jointed goatgrass in small grain crops without deleteriously affecting the crop.
2. Description of the Art
Jointed goatgrass (Aegilops cylindrica) is a winter annual grass that is a major weed species in the winter wheat producing areas of the western United States. Over 3 million acres of winter wheat in the western U.S. are infested with this weed, reducing yields by about 15-20%. There is no selective herbicide available for the control of jointed goatgrass in a grass crop, e.g., a small grain crop. This is because jointed goatgrass and winter wheat are genetically similar (they share the same D genome). Further, the life cycles of jointed goatgrass and winter wheat and winter barley are very similar. Another problem is that jointed goatgrass seed is viable in the soil for at least four years. At the present time, producers must grow spring crops continuously for a minimum of three years to reduce the jointed goatgrass seed reservoir in the soil to a manageable level. This cultural control method has a serious economic disadvantage because the yield of spring wheat is about 40% lower than winter wheat.
Use of antagonistic microorganisms for biological control of some weeds have been reported. However, no bacterial strain has been previously found which would control the weed jointed goatgrass; additionally, no procedure for the selection of bacteria which inhibit jointed goatgrass in small grain crops has been reported. Because the physiological characteristics required for a bacterial strain to control weeds are very specific as to (1) the weed to be controlled; (2) the mode of action of weed control; (3) the activity and ecological niche of the microorganism; and (4) cultural practices and soil and climatic conditions favorable for control, information about microorganism treatments for control of weeds other than jointed goatgrass cannot be used to predict strains of microorganisms which would reduce jointed goatgrass under field conditions or predict criteria for selecting such strains.